Bovine lameness ranks third among the leading causes of cows leaving their herd.
Lameness is a multifactorial disease, related to the quality of cow management in our dairies. Some of the contributing factors to bovine lameness are cow comfort, walking surfaces, time spent standing on concrete, hoof health, hoof trimming frequency and nutrition.
Preventing bovine lameness is economically more rewarding than treating lameness after it’s detected. Controlling lameness is challenging and demands setting goals to measure progress. Realistic goals for new hoof sole and wall lameness in sand-bedded herds would be less than 0.5 percent per month. For mattress-bedded herds a rate of less than 1 percent new cases would be the goal. Compare these goals to the benchmarks for digital dermatitis (hairy heel warts) – less than 2 percent of the cows infected per month – and less than 0.1 percent of the cows per month should experience foot rot.
Hoof anatomy
The bovine hoof is a complex structure with plenty of sites where disease and other problems can occur. The hoof grows at the rate of 0.25-inch per month, and it’s composed of the outer wall, sole, white line and heel. The hoof wall, sole and heel are made of keratin (horn epidermis) material which is produced by an underlying corium layer. The corium contains the nerve and blood supply. The white line forms the junction between the sole and wall. The two claws of the hoof are divided by the interdigital space and connected by smooth, hairless skin.
Mature hoof shape is a balance of hoof growth and wear. The toe will tend to wear slower since it is harder and the heel will wear faster. The outer claw of the hind hoof grows faster than the inner claw; the opposite is found on the front. The heel bulb area responds to weight by compression. The major weight- bearing area of the hoof is the outside part of the outside claw.
Diagnosing lameness
A “sore foot” is a description of lameness but not a diagnosis. The most common causes of bovine lameness come from a group of diseases related to abnormalities of the claw horn layer of the hoof. The group includes white line disease and sole ulceration disease; research from the University of Florida indicates that these two diseases alone represent 65 percent of the reported hoof problems.
Nutritional laminitis has been thought to be the primary factor contributing to this disease complex. Research has indicated that claw lesions may be associated with hormonal events at calving. Enzymes within the corium layer may be activated at this time to create a loosening of components within the hoof. These same enzymes can be activated by a toxin released from bacteria in the rumen when ruminal pH is 5.5 or less from nutritional acidosis.
What to look for
Here are some of the most commonly diagnosed bovine hoof pathologies:
• White line disease starts with fissures due to hemorrhage and poor- quality horn formation.
• Sole ulcer is an opening in the sole horn that exposes the corium. Location is the rear middle part of the sole.
• Sole separation results when the corium layer is damaged and produces weak horn tissue for a period of time and then resumes normal production of tissue.
• Sole and white line hemorrhages originate from damage to the corium with blood being incorporated into the horn as it develops. A sole abscess or white line abscess can occur if the hemorrhage becomes infected.
• Toe ulcer occurs when the sole is too thin at the toe and the corium is exposed to environmental bacteria; an abscess can form.
• Thin sole will occur from excessive hoof wear associated with long- distance walks on abrasive concrete. Poor sole horn tissue integrity is also a contributor.
• Heel horn erosion is the development of fissures in the heel horn. Normal heel horn tissue should be smooth, but constant exposure to wet conditions can contribute to deterioration of the heel.
• Digital dermatitis is a superficial infection that occurs at the commissures of the interdigital space, primarily at the rear but it can occur at the front aspect of the hoof. Etiology appears to be multifactorial. The lesions are painful and the resulting lameness is pronounced.
• Foot rot is a bacterial disease. Lesions are in the interdigital skin area and are recognized by inflammation and swelling of the hoof.
Significant risk factors of bovine lameness include heat stress, reduced daily laying time and periods of standing too long in the parlor holding area, in stalls, in alleys or perching in stalls. Long periods of weight-bearing on concrete may exacerbate claw horn pathology.
Managing lameness
Here are some steps you can take to help reduce and relieve lameness in your dairy herd:
• Locomotion scoring and identification of lame animals in the beginning stages of the lameness.
• Foot trimming, both on a routine schedule and for therapeutics.
• Management at calving: The hormonal, metabolic changes at calving have a profound effect on the structural integrity of the hoof.
• Management of heifer introduction into the herd: Transitioning heifers socially and nutritionally into the lactating herd with minimal stress will reduce potential lameness. If a heifer is lame in her first lactation, she is three times more likely to be lame in her second lactation.
• Monitor laying times. Eleven to 14 hours of recumbency per day should be the guideline.
• Freestall design for cow comfort when getting up or down.
• Improve concrete surfaces. Inspect walking surfaces for any areas that could cause bruising, punctures or excessive wear.
• Strategic and regular use of footbaths.
• Nutrition and nutritional management to avoid subacute ruminal acidosis.
• The use of well-researched nutritional products that aid in hoof health, such as biotin and chelated trace minerals.
• Providing a recovery pen for lame cows during the convalescent period.
Proactively monitoring and managing the hoof health of your dairy herd does take some effort but the returns are worth it. Preventing lameness costs less in time and money than treating lameness. And, like nearly everything else that promotes healthier cows, you’ll see better production results. PD
Dr. Robert Ovrebo is a DVM on staff at the Form-A-Feed and TechMix companies, headquartered in Stewart, Minnesota. For more information, call Dr. Ovrebo at 800-422-3649 or send an e-mail to articleinfo@formafeed.com
Robert G. Ovrebo
Veterinarian with Form-A-Feed
articleinfo@formafeed.com
